Which of the following is incorrect?
An element which has high electro negativity always has high electron gain enthalpy
Elements with high electronegativity usually have high electron gain enthalpies, but this is not true for all the elements. If we take the example of Nitrogen, it's electronegativity is one of the highest. But if we look at its electron gain enthalpy, we actually need to supply energy to add the electron because Nitrogen has a half-filled configuration which is stable.